Usually, a portable drilling machine uses a commercial AC power supply, and when a power switch is turned on by the user, an electromagnet housed in a body base is energized so that the body is firmly attracted to a workpiece such as an iron plate by a magnetic force of the electromagnet. When the user turns on a start switch with the body being fixed to the workpiece in this manner, a drive motor housed in the body is activated to rotationally drive a cutting tool such a drill. When the user then lowers the cutting tool by a manual handle or lever operation for example to press it against the workpiece, the cutting tool rotatingly advances to cut (e.g., drill) the workpiece (e.g., Patent Document 1).